MAIN LABORATORY
Although increasing attention is being given to the analysis of organic compounds in water due to the growing anthropogenic impact on the environment, the significance of inorganic indicators, examined within this Department, must not be overlooked. Inorganic indicators encompass basic physicochemical parameters (temperature, pH, electrical conductivity, salinity), nutrients and ions, oxygen regime, as well as metals in water and sediment.
Monitoring water pH provides insight into acidity or alkalinity, which may fluctuate in cases of pollution. Electrical conductivity reflects the total amount of dissolved substances in the water, with distilled water exhibiting almost no conductivity. Conductivity also depends on the composition of the riverbed; waters flowing over soluble rock substrates will have higher conductivity.
Total dissolved solids in water comprise dissolved inorganic salts, primarily cations such as calcium, magnesium, sodium, potassium, and silicates, as well as anions such as carbonates, chlorides, and sulphates. Cations and anions may enter water through physical and chemical leaching of surrounding soil and rocks, as well as through anthropogenic means, such as acid rains containing sulphur oxides and chlorides. Monitoring their concentrations is crucial, as biological processes may lead to their accumulation in living organisms. For example, aquatic crustaceans utilise calcium for exoskeleton formation, while the microscopic algas called diatoms construct their frustules from silicates. Nutrients in water include ammonium, nitrites, nitrates, orthophosphates, total nitrogen, and total phosphorus, which circulate within biological processes. The predominant source of nutrients in water is anthropogenic, stemming from wastewater and agriculture, making their concentration an essential parameter for assessing water quality.
Oxygen is essential for most life forms on Earth, which is why the determination of oxygen concentration and saturation in water a crucial aspect of water quality monitoring. Besides oxygen concentration and saturation, the oxygen regime also includes measurements of biological and chemical oxygen demand, which indicate the amount of oxygen required for the biological degradation or chemical oxidation of organic matter.
As metals are present throughout the entire ecological system, determining their concentrations in water (both in total and in its dissolved form) is of great importance. Dissolved metals are more bioavailable and, therefore, exert a greater impact on ecosystems. Their effects on plants, animals, and humans depend on the type and chemical properties of each metal.
Metals that are not biologically essential, such as mercury, cadmium, nickel, chromium, and lead, are generally toxic even at very low concentrations. On the other hand, there are also essential, biologically important metals that are crucial for metabolic processes and the regulation of many biochemical functions. Essential metals such as iron, copper, zinc, cobalt, manganese, and molybdenum are important indicators of the aquatic environment. However, excessive concentrations of those metals may as well lead to various toxic effects.
Since sediment represents a record of metal concentrations over an extended period, the determination of metal concentrations in sediment is of great importance in the Department for Inorganic Indicator Testing, allowing for the observation of both lithological and anthropogenic influences. The determination of metals in sediment is also crucial because sediment can act as a potential reservoir of metal pollution, which, under certain conditions, can be released back into the environment, thereby affecting biodiversity as well as human health.
The Department for Inorganic Indicator Testing employs a range of analytical methods, from classical titrimetric methods for determining chemical oxygen demand to highly sophisticated techniques such as ion chromatography coupled with tandem mass spectrometry for ion and glyphosate detection, as well as inductively coupled plasma mass spectrometry (ICP-MS) for metal analysis.
A fully automated system for determining basic physico-chemical parameters and chemical oxygen demand will soon be introduced, further enhancing the precision and efficiency of inorganic indicator analysis in water and sediment.